SAN FRANCISCO — In 2008, when the archbishop of the Church of Sweden convened a conference on the threats posed by climate change, the church’s investment managers took notice. The next year, they began removing fossil fuel companies from the church’s financial portfolio — a process that was completed last month with the removal of several natural gas companies.

Climate change “is an important issue for the church and its members,” said Anders Thorendal, the chief investment officer of the Church of Sweden. It did not make sense, he added, to keep fossil fuel companies — whose products result in climate-warming emissions — in the church’s portfolio.

The movement to end investments in fossil fuel companies began with universities, but religious institutions are joining as well. Just this month, the Anglican Diocese of Perth, Australia, announced plans to divest itself of holdings in fossil fuels, and the Presbyterian Church of New Zealand said it would consider doing the same.

The sums that many churches control can be modest: The Church of Sweden’s central portfolio, for example, is about $830 million, far less than the endowments of major universities. Over all, groups controlling more than $50 billion in assets have pledged to divest themselves of investments in fossil fuels, according to a study last month by Arabella Advisors.

But churches can lend a powerful moral sway to the movement, said Marion Maddox, an expert in religion and politics at Macquarie University in Australia.

“The amount of money we’re talking about isn’t going to bankrupt any fossil fuel companies,” Dr. Maddox said. Divestment by the churches, however, “has the effect of getting people to stop and think, ‘Is this respectable to be involved with?’ ”

Religious institutions were in the vanguard of the movement to divest themselves of holdings in apartheid-riven South Africa a few decades ago, according to a recent study of divestment by Oxford academics. Now, climate change has come into the spotlight as an issue poised to affect some of the world’s poorest communities, and groups from all faiths have pushed for action. But it is youthful and idealistic students who have largely taken the lead in urging the removal of fossil fuel investments from endowments. Last week, the University of Glasgow said it had become the first British university to announce plans for full divestment. Philanthropies and local governments have also joined the movement.

But many institutions, including churches, have been cautious. The Church of England, for example, debated the issue this year but has so far resisted pressure from activists to divest itself of investments in fossil fuels. The church is still reviewing the matter, and a new policy on climate change and investment is scheduled to be published next year. Edward Mason, the head of responsible investment for the church’s commissioners, said in a statement that the Church of England continued to engage with companies “on matters such as their carbon emissions management, deployment of capital to fossil-fuel extraction and lobbying activities.”

Michael Northcott, a professor of ethics at the University of Edinburgh’s School of Divinity, who has urged the Church of England and other institutions to divest themselves of holdings in fossil fuels, said, “Churches in the main are not accustomed to standing apart from Western culture on big issues like where they put their money

The World Council of Churches, an umbrella group in Geneva, is one of the most significant religious bodies to divest so far, though it does not dictate the actions of its member churches. The Uniting Church in Australia, one of that country’s largest Christian denominations, has announced divestment plans, as has the Anglican Church in New Zealand. In the United States, the United Church of Christ said last year that it would move toward fossil-fuel divestment.

So far, Christian churches seem to have embraced the divestment movement most strongly, though other religious groups are also concerned about climate change. Jewish groups tend to feel “conflicted” about divesting, said Jonathan Crane, a scholar of bioethics and Jewish thought at Emory University’s Center for Ethics.

“Many of these Jewish organizations would certainly resonate with climate change concerns and take them seriously and think that actions should be done,” he said. “But they would raise an eyebrow, have some anxieties or ambivalences, about the actual strategy of divestment,” because of a perception that similar strategies can get used against Israel. (Some institutions have used a separate divestment movement to pressure Israel over its policies toward the Palestinians.)

The Shalom Center, a Jewish group in Philadelphia that is active on environmental issues, has embraced a concept akin to fossil fuel divestment but calls it instead “move our money/protect our planet.”

Smaller or independent religious groups may have an easier time divesting, according to experts. Mr. Thorendal, of the Church of Sweden, said that his church’s modest size made it easier to find financial managers in tune with sustainability-oriented investing. The church ran an analysis of how past investments would have fared without fossil fuels and found that eliminating such companies left both annual and long-term returns about the same. “We didn’t really see a large financial risk,” Mr. Thorendal said.

The Church of Sweden got rid of coal and oil companies in its portfolio in 2009, and more recently decided to end its few investments in natural gas companies as well, as the environmental impacts of gas came under increasing scrutiny.

Mr. Thorendal emphasized that it is important not only to divest from fossil fuels, but to invest in companies whose work benefits the environment.

“Divesting is not really what’s driving us,” he said. “What’s driving us is to find the best solutions, the best companies.”

To that end, the Church of Sweden invests in several sustainability-oriented funds managed by Generation Investment Management, a firm co-founded by Al Gore, the climate change campaigner and former United States vice president. The church also seeks out niche opportunities: Last year, for example, it began investing in a microfinance fund as well as another fund dedicated to sustainable agriculture that avoids deforestation. Finding such opportunities has gotten easier in recent years, Mr. Thorendal said.

Religious officials are closely watching a few large groups that would be especially influential if they chose to divest. A move by the Lutheran church in Germany would carry symbolic weight, Dr. Northcott said, because it is the largest national church in the European Union.

But the ultimate prize for anti-fossil-fuel campaigners would be the Vatican, which is powerful both morally and financially. A “divest the Vatican” movement has sprung up.

Dr. Northcott rated the chances of Pope Francis’s “significantly shifting the Vatican line” as minimal, although the pope has often urged his followers in the Roman Catholic Church to care for creation.